@article{AOUINA2021113006,
title = "Molecular variation and fluorescent turn-on detection of chromium(III) by three ESIPT-reactive 2,2'-(1,4-phenylenebis(5-phenyl-1H-imidazole-4,2-diyl))diphenols",
journal = "Journal of Photochemistry and Photobiology A: Chemistry",
volume = "406",
pages = "113006",
year = "2021",
issn = "1010-6030",
doi = "https://doi.org/10.1016/j.jphotochem.2020.113006",
url = "http://www.sciencedirect.com/science/article/pii/S1010603020308030",
author = "Aroua Aouina and Hammed Olawale Oloyede and Raymond Akong Akong and Jawher Abdelhak and Helmar Görls and Winfried Plass and Abiodun Omokehinde Eseola",
keywords = "Chromium(III), Fluorescent chemosensor, Structure-property correlation, Sustainable environment, ESIPT process",
abstract = "Three novel bis-imidazole-phenol dyes 1–3 have been designed with deliberate incorporation of a pair of O–H…N donor-acceptor units on each dye in order to enable Excited State Intramolecular Proton / electron Transfer (ESIPT) capability, its desirable red-shifted emissions and consequent reduction of fluorescence characteristics, which in turn became applicable for fluorescence turn-on response in metal ion sensing. Molecule 1 was confirmed by single crystal X-ray analysis. Their quantum yields in acetonitrile solutions are generally suitable (Φ = 0.30 for 1, Φ = 0.06 for 2 and Φ = 0.08 for 3) and they display fluorescence turn-on sensitivity towards chromium(III). The selectivity features of fluorophores 2 and 3 for Cr(III) are remarkable. The blue-shift of emission bands coupled with the emission turn-on after introduction of Cr(III) confirms that the ESIPT capability of the fluorophores contributes to the low emission properties of the molecules and that emission turn-on during fluorescence detection succeeds by elimination of the ESIPT possibility. Therefore, it could be concluded that the ESIPT feature is a vital tool to utilize for fluorescent sensor designs. Job plot analysis indicates a 2 : 1 stoichiometry of metal : sensor. Results of interference studies also favours potential application of the ESIPT dye 3 for detection of chromium(III). Molecular variation effects were discussed."
}